In this code, a TreeSet named frenchCities is created and populated with the following cities: "Paris", "Marseille", "Lyon", "Lille", and "Toulouse". The TreeSet class in Java stores elements in a sorted order according to their natural ordering, which, for strings, is lexicographical order.
Sorted Order of Elements:
When the elements are added to the TreeSet, they are stored in the following order:
"Lille"
"Lyon"
"Marseille"
"Paris"
"Toulouse"
headSet Method:
The headSet(E toElement) method of the TreeSet class returns a view of the portion of this set whose elements are strictly less than toElement. In this case, frenchCities.headSet("Marseille") will return a subset of frenchCities containing all elements that are lexicographically less than "Marseille".
Elements Less Than "Marseille":
From the sorted order, the elements that are less than "Marseille" are:
Therefore, the output of the System.out.println statement will be [Lille, Lyon].
Option Evaluations:
A. [Paris]: Incorrect. "Paris" is lexicographically greater than "Marseille".
B. [Paris, Toulouse]: Incorrect. Both "Paris" and "Toulouse" are lexicographically greater than "Marseille".
C. [Lille, Lyon]: Correct. These are the elements less than "Marseille".
D. Compilation fails: Incorrect. The code compiles successfully.
E. [Lyon, Lille, Toulouse]: Incorrect. "Toulouse" is lexicographically greater than "Marseille".
